Lubricant composition for inhibiting valve recession

ABSTRACT

A METHOD FOR IMPROVING THE WEAR PROPERTIES OF EXHAUST VALVES OF NATURAL GAS FUELED NTERNAL COMBUSTION ENGINES IS DISCLOSED. THE METHOD INVOLVES LUBRICATING THE ENGINE WITH A COMPOSITION WHICH COMPRISES OIL OF LUBRICTING VISCOSITY, ALKALINE EARTH METAL SULFONATE, AND AT LEAST ONE ALKALINE EARTH METAL SALT OF A CONDENSATION PRODUCT OF AN ALKYLENE POLYAMINE, AN ALDEHYDE AND A SUBSTITUTED PHENOL.

United States Patent Office 3,798,163 Patented Mar. 19, 1974 3,798,163 LUBRICANT COMPOSITION FOR INHIBITING VALVE RECESSION Robert C. Palmer, Markham, BL, assignor to Atlantic Richfield Company, New York, N.Y. No Drawing. Filed July 23, 1971, Ser. No. 165,732 Int. Cl. Cm N40 US. Cl. 252-33.4 17 Claims ABSTRACT OF THE DISCLOSURE A method for improving the wear properties of exhaust valves of natural gas fueled internal combustion engines is disclosed. The method involves lubricating the engine with a composition which comprises oil of lubricating viscosity, alkaline earth metal sulfonate, and at least one alkaline earth metal salt of a condensation product of an alkylene polyamine, an aldehyde and a substituted phenol.

This invention relates to a method for improving the performance of natural gas fueled internal combustion engines. More particularly, the present invention relates to a method for inhibiting exhaust valve recession in natural gas fueled internal combustion engines.

Many internal combustion engines in use today are fueled by natural gas. The trend in designing these engines has been toward higher and higher power outputs. The resulting increased operating severity has lead to added incidents of engine exhaust valve wear commonly known as valve recession or sink. Engines operating under high load conditions may experience rapid wear of the exhaust valves and/or the exhaust valve seat. This type of wear is commonly referred to as valve recession or sink because as the wear occurs, the valve head recedes or sinks into the cylinder head of the engine.

Metallurgical improvements in valve and valve seat materials, for example, Stellite valve inserts at the points of contact between the valve and valve seat, have given some relief to the valve sink problem. However, this means of lessening the valve wear problem has met with only limited success. In many instances, the natural gas fueled engines even equipped with Stellie inserts operate marginally or poorly with respect to valve wear.

Therefore, one of the objects of the present invention is to provide a method to control the exhaust valve wear in natural gas fueled internal combustion engines. Another object of the present invention is to provide a method by which exhaust valve wear in natural gas fueled internal combustion engines is inhibited. Other objects and advantages of this invention will become apparent hereinafter.

The present invention relates to the use of certain defined lubricating oil compositions in internal combustion engines which utilize natural gas as fuel. The lubricating oil compositions for use in the present invention comprise a major proportion of oil of lubricating viscosity; at least one alkaline earth metal sulfonate present in an amount suflicient to improve the detergency of said composition; and at least one alkaline earth metal salt of a condensation product of an alkylene polyamine, an aldehyde and a substituted phenol, said alkaline earth metal salt being present in an amount sufiicient to inhibit the recession of the engines exhaust valves into the engine cylinder head.

The alkylene polyamines suitable for use in the present invention have the following structure:

wherein R is a alkylene radical containing from about 2 to about 6 carbon atoms, and n is an integer from 1 to about 10. The aldehydes suitable for use in the present invention contain from 1 to about 3 carbon atoms per molecule. The suitable substituted phenols may be characterized as alkylated monohydric phenols containing at least one alkyl group of sufiicient size to impart oil solubility to the alkaline earth metal salt of the condensation product noted previously.

Exhaust valve recession inhibition is achieved in the method of the present invention by maintaining, or causing to be maintained, a lubricating amount of the oil compositions defined previously on the engine components of an internal combustion engine requiring lubrication. The term exhaust valve recession as used herein refers to wear at the points of contact between the exhaust valve itself and the exhaust valve seat in the engine cylinder head. In other words, the exhaust valve itself and/or the valve seat may become worn, thus causing the valve to recede into the engine cylinder head. Therefore, exhaust valve recession may result from wear to the exhaust valve itself and/or the exhaust valve seat in the engine cylinder head.

The internal combustion engines to which the present invention is applicable may be characterized as those operated on, i.e., fueled by, substantially lead-free natural gas. Included among these engines are, for example, stationary engines used in liquid or gas pipeline service. The applicable engines may be associated, i.e., used to power or carried by, transportation means. In fact, any internal combustion engine, including two cycle engines, four cycle engines and rotary piston driven engines, which is operated on substantially lead-free natural gas can be utilized in the practice of the present invention. Particularly outstanding inhibition of exhaust valve recession has been obtained when the present invention is applied to a four cycle internal combustion engine and, for this reason, this type of engine is preferably utilized when practicing the method of the present invention. As noted previously, current engineering practice makes use of Stellite valve inserts to reduce exhaust valve recession. The present invention may be used to inhibit exhaust valve wear in engines with or without Stellite exhaust valve inserts, however, for maximum benefits, e.g., maximum exhaust valve recession inhibition, of the present invention, it is preferred that the engine be equipped with Stellite exhaust valve inserts at the points of contact between the exhaust valve and valve seat.

The term natural gas may be defined as a substantially hydrocarbonaceous compound or mixture of compounds which has the property of being substantially, i.e., greater than about by weight, vaporous at atmospheric pres sure and 50 F. The compound or mixture may contain minor amounts of other elements, such as nitrogen, oxygen, sulfur and the like which do not substantially affect. the hydrocarbon character. The fuel should also be essentially lead-free. This latter term may be defined such that the fuel contains less than about 0.03 gm./lb., generally less than about 0.01 gm./ lb. of tetraethyl lead or its equivalent in terms of weight of lead.

Typical examples of the oils used in the compositions utilized in the present invention are those conventionally used in lubricant manufacture. The suitable lubricating oils include those having a viscosity within the range from about 50 SUS to about 2000 SUS, preferably in the range from about 950 SUS to about 1150 SUS, at 100 F. These oils may be refined or otherwise processed to produce an oil having the desired quality. Although mineral oils are preferred, the oil may be synthetic in nature. Typical of the oils used in the present invention is a mineral oil having a viscosity of about 1000 SUS at 100 F. Combinations of two or more different oils in a single lubricating composition are within the scope of the present invention. The lubricating oil comprises a major proportion, preferably at least about 70%, still more preferably at least about 85% by weight, of the total composition.

In order to improve the lubricating qualities of the com positions of the present invention, it is preferred to include from about 0.1% to about 10%, more preferably 0.1% to about 5%, by weight of a compound selected from the group consisting of alkali metal sulfonates, alkaline earth metal sulfonates and mixtures thereof. The preferred sulfonate for use in the compositions of the present invention are the alkaline earth metal sulfonates, more preferably the calcium sulfonates.

Sulfonates derived from sulfonic acids having about 12 to about 200 carbon atoms per molecule are of particular usefulness in the present invention. Among the sulfonic acids are the following: mahogany sulfonic acids, petrolatum sulfonic acids, monoand polywax substituted naphthalene sulfonic acids, phenol sulfonic acids, diphenyl ether sulfonic acids, diphenyl ether disulfonic acids, naphthalene disulfide-sulfonic acids, naphthalene disulfide disulfonic acids, diphenyl amine disulfonic acids, cetylphenol mono-sulfide sulfonic acids, cetoxy capryl-benzene sulfonic acids, di-cetyl thianthrene sulfonic acids, such as cetyl chlorobenzene sulfonic acids, cetyl-phenol sulfonic acids, cetyl-phenol disulfide sulfonic acids, cetyl-phenol mono-sulfide sulfonic acids, cetoxy capryl-benzene sulfonic acids, di-cetyl thianthrene sulfonic acids, di-lauryl beta-naphthaol sulfonic acids and di-capryl nitronaphthalene sulfonic acids, aliphatic sulfonic acids, such as parafiin wax sulfonic acids, unsaturated parafiin wax sulfonic acids, hydroxy substituted parafiin wax sulfonic acids, tetraisobutylene sulfonic acids, tetra-amylene sulfonic acids, chloro-substituted parafiin Wax sulfonic acids, nitroso paraffin wax sulfonic acids, etc., cycloaliphatic sulfonic acids, such as petroleum naphthene sulfonic acids, cetyl-cyclopentyl sulfonic acids, lauryl-cyclohexyl sulfonic acids, bis-(diisobutyl)- cyclohexyl sulfonic acids, monoand polywax substituted cyclohexyl sulfonic acids, etc.

With respect to the sulfonic acids, it is intended herein to employ the term petroleum sulfonic acids to cover all sulfonic acids which are derived at least in part from petroleum products. Additional examples of sulfonic acids and/or the alkali and alkaline earth metal salts thereof which can be employed as starting materials are disclosed in the following United States patents: 2,174,110; 2,174,- 560; 2,174,508; 2,193,824; 2,197,800; 2,020,791; 2,212,- 786; 2,213,360; 2,228,598; 2,233,676; 2,239,974; 2,263,- 312; 2,276,090; 2,276,097; 2,315,514; 2,319,121; 2,321,- 022; 2,333,568; 2,333,788; 2,335,259; 2,337,552; 2,346,- 568; 2,366,027; 2,374,193 and 2,383,319.

The alkylene polyamines suitable for use in the present invention have the following structure:

wherein R is an alkylene radical containing from about 2 about 6 carbon atoms, and n is an integer from 1 to about 10. Typical alkylene polyamines include diethylenetriamine, triethylenetetramine, tetraethylenepentamine and the like. The preferred alkylene polyamine for use in the present invention is diethylenetriamine.

As noted previously, the aldehydes suitable for use in the present invention are aliphatic aldehydes which contain from one to about 3 carbon atoms per molecule. The preferred aldehyde for the use in the present invention is formaldehyde.

The substituted phenols contemplated herein are the alkylated monohydric phenols having at least one alkyl group of sufiicient length to impart oil-solubility to the condensation products. Such phenols are further characterized as having at least one ortho or para position which is available as a reaction site in the nucleus. Representative alkyl phenols which can be employed are those in which the alkyl group contains from about 4 to about 24 carbon atoms, and preferably those having from about 8 to about 24 carbon atoms, such as, for example, namyl phenol, diamylphenol, octyl phenol, nonyl phenol, p-tert-octyl phenol, a mixture of phenols, wax alkylated phenols and the like. If desired, the alkylated phenols may also contain one or more substituent groups such as nitro, alkoxy, and the like. Particularly outstanding results have been obtained using the salts of condensation products derived from octyl phenol and for this reason this alkylated phenol is more preferred.

The alkaline earth metal salts of the condensation products useful in the present invention may be prepared in two steps, i.e., condensation and salt formation. The condensation reaction may be carried out as follows. In order to obtain oil compatible, i.e., soluble, dispersible or miscible without continuing agitation, condensation products, alkaline polyamine, aldehyde and substituted phenol may be reacted together at a elevated temperature such as a temperature in the range of about F. to about 350 F. in the presence or absence of a solvent. The reactants may be employed in a ratio of at least about 0.5 mole of each of aldehyde and phenol for every heavy basic nitrogen atom present in the alkaline polyamine with the upper limit being about 2 moles each of aldehyde and phenol for every heavy basic nitrogen atom in the amine. The desired metal of the alkaline earth group is preferably introduced by reaction of its oxide or hydroperoxide with the condensation product to form the salt useful in the present invention. It is preferred to use the calcium salt of the amine-aldehyde-phenol condensation product when practicing the present invention.

' As noted above, the condensation reaction takes place at a temperature of about 100 F. to about 350 F., preferably at temperatures of about 100 F. to about 270 F., and can be conventionally carried out in the presence of any suitable solvent such as benzene, toluene and the like which can be recovered from the condensation product. If desired, the reaction may be carried out in a mineral oil. No special equipment is required for the condensation reaction and any suitable pot type reactor can be employed. The oil soluble alkaline earth metal salts of these condensation products can be prepared by neutralization of the condensation product with a basic compound, such as the desired alkaline earth metal hydroperoxide, or by neutralization with a metal oxide or hydroperoxide followed by preparation of the metal salt (metathesis). Preferably when carrying out the neutralization of the condensation product in mineral oil to form the calcium salt, additional mineral oil of the type employed in preparing a mineral oil concentrate is added to the reaction mixture together with lime and a small amount of water to facilitate the neutralization.

The alkaline earth metal salts of the condensation products are included in the lubricating compositions utilized in the present invention in an amount sufiicient to inhibit the recession of the exhaust valves of the engine being lubricated. It is preferred that these alkaline earth metal salts comprise from about 0.1% to about 6% by weight of the total lubricating oil composition. Optimum results are obtained when the alkaline earth metal salt concentrations range from about 2% to about 4% by weight of the total lubricating oil composition.

The fully formulated lubricating oil compositions suitable for use in the present invention may include various additives to improve the lubricating and other properties of these compositions.

For example, the lubricating oil compositions may contain one or more compounds selected from the group consisting of alkali metal phenate, alkaline earth metal phenate and mixtures thereof, said salt being present in an amount sufiicient to contribute alkalinity to the lubricating composition. This alkalinity is desired, for example, to neutralize certain acids formed during engine operation. When these phenates are employed in the lubricating compositions, it is preferred that they be present in an amount from about 0.1% to about 8%, more preferably from about 0.2% to about 5.0%, by weight of the total composition. The preferred phenates for use in the present invention are the alkaline earth metal phenates, more preferably the calcium phenates. The phenates may be polymerized, for example, by reaction with elemental sulfur to form sulfurized phenates, and/or overbased, by treatment with carbon dioxide. Other polyphenates, such as carbon bridged polyphenate, whether overbased or not are also suitable for use.

One method for preparing sulfurized phenates is given in U.S. Pat. No. 2,680,096. This patent also discloses a description of the calcium phenates, both sulfurized and unsulfurized, which are suitable for use in the present invention. The unsulfurized calcium phenates have the following formula:

wherein A is an essentially hydrocarbon aromatic radical, preferably a benzene radical, R is a cyclic, straightchained or branched-chained, saturated, essentially hydrocarbon radical having from 4 to 30 carbon atoms, 0 represents oxygen, and a is an integer having a value of from 1 to 5.

By essentially hydrocarbon (i.e., hydrocarbonaceous) radical is meant those radicals which are composed mainly of hydrogen and carbon, and include such radicals which contain, in addition, minor amounts of substituents, such as chlorine, bromine, oxygen, sulfur, nitrogen and the like, which do not substantially aifect their hydrocarbon character. Examples of suitable hydrocarbonaceous radicals include alkyl radicals such as butyl, hexyl, octyl, decyl, dodecyl, hexadecyl, eicoxyl, .triacontyl radical; radicals derived from petroleum hydrocarbons, such as white oil, wax, olefin polymers (e.g., polypropylene and polybutylene), etc.; aryl radicals such as phenyl, naphthyl, etc.; aralkyl radicals such as phenyloctyl, phenyldecyl, phenyloctadecyl, etc.; alkaryl radicals such as amylphenyl, cetylphenyl, etc.; and cyclic non-benzenoid radicals, such as cyclohexyl, bornyl, etc.

Examples of calcium phenates include the calcium salts of octyl phenol, decyl phenol, dodecyl phenol, tetradecyl phenol, hexadecyl phenol, triacontyl phenol and the like.

Both the unsulfurized and the sulfurized phenates can be overbased with carbonate by treating the phenate with carbon dioxide such as disclosed in U.S. Pat. No. 3,036,971.

It is preferred that the lubricating compositions of the present invention include at least one ashless dispersant. When these ashless dispersants are included in the compositions of this invention, they comprise from about 0.5% to about 6% by weight of the total composition.

In general, the ashless dispersants suitable for use are compounds which comprise an oil solubilizing tail and polar dispersant head. Many ashless dispersants fitting this general description are known to the art and are commercially available. For example, basic polyamines substituted with long chain hydrocarbons having from about 30 to about 200 carbon atoms to provide oleophilic character are suitable for use in the present invention. Specific examples of this type of ashless dispersant include the polyamines-polyalkylene alkenyl succinimides in which the alkenyl group contains from about 30 to about 250 carbon atoms, the divalent alkylene radicals, which number from about 2 to about 6, each contain from about 1 to about 3 carbon atoms; and the N-dialkylaminoalkyl alkenyl succinimides in which the alkenyl group contains from about 30 to about 250 carbon atoms and the divalent alkylene radical along with the two alkyl radicals contain a total of less than about 10 carbon atoms. Typical examples are set forth in U.S. Pat. No. 3,018,291, which is hereby incorporated by reference into the present application. The required polarity may be supplied by groups containing, for example, oxygen, halogen, sulfur, phosphorous as Well as nitrogen and mixtures thereof. For example, an ashless dispersant can be derived by reacting hydrocarbon polymer containing from about 30 to about 200 carbon atoms with P 8 Typical examples are set forth in U.S. Pat. No. 3,003,964; British Pat. No. 815,810; U.S. Pats. Nos. 3,256,189 and 3,256,194, which patents are hereby incorporated by reference into the present application. All of these suitable ashless dispersants may be characterized as compounds comprising at least one hydrocarbon portion of sufiicient size to render the compound oil soluble and at least one non-metallic polar portion which provides a substantial part of the dispersant action.

In addition to the additives already described, lubricating oil compositions contemplated herein may contain other agents, such as pour point depressants, anti-foam agents, oiliness agents, blooming agents, compounds for enhancing the viscosity index of the lubricating oil, peptizing agents, etc.

Corrosion and oxidation inhibitors may also be added to the lubricating compositions of the present invention. An example of such an inhibitor is one that is essentially a chloro-sulfur substituted olefin having from about 10 to about 24 carbon atoms per molecule, preferably from about 14 to about 18 carbon atoms. A particularly preferred compound is commercially available as a mixture of about a 50% by weight active inhibitor in a mineral oil carrier. This mixture contains about 17.5% by weight of sulfur, about 1.8% by weight of chlorine and has an average carbonation olefin content of about 16 canbon atoms. All the additives noted above may be present in compositions used in the present invention in an amount sufiicient to achieve their function. For example, it is preferred that the inhibitor noted above (on a carrier-free basis) be present in the compositions of the present invention in an amount from about 0.01% to about 2.0%, preferably from about 0.05% to about 1.0%, by weight of the total composition.

The lubricating compositions utilized in the present invention may be prepared in any conventional manner. For example, the various components may be brought together and mixed at a slightly elevated temperature, i.e., from about F. to about F., to insure a uniform composition.

In many instances, the additives incorporated into the lubricating compositions utilized in the present invention are available as a mixture in a mineral oil or other solvent carrier, Unless otherwise noted, the weight proportions given above refer to the amount of active material on a carrier or solvent-free basis.

EXAMPLES 1 TO 3 The following examples illustrate the improved exhaust valve wear obtained by the present invention.

7 The following composition was prepared at a slightly elevated temperature, i.e., from about 100 F. to about 130 F., to insure product uniformity.

Component: Weight parts Mineral oil, about 1000 SUS at 100 F 87.8 Calcium sulfonate 1 3.6

Calcium salt of the condensation product of octyl phenol, formaldehyde and diethylenetriamine 2 5.5 Calcium phenate 3 0.5 Ashless dispersant 4 2.5 Corrosion inhibitor 5 0.1 Anti-foam agent 6 0.001

A mixture of about 45% by weight of a calcium sulfonate in a mineral oil carrier. The sulfonate contains, on an average, about 26 carbon atoms per molecule and is derived from petroleum sources. The sulfonate-oil mixture has a total base number (obtained using test D-664) of about 25.

Blended into the composition as a mixture of about 50% by weight of mineral oil and 50% by weight of the calcium salt of the condensation product. The condensation product was prepared by reacting the octyl phenol, formaldehyde and diethylenetriamine in a mole ratio of about 3.1 3.8:1.0.

3 A mixture of about 50% by weight of mineral oil and about 50% by weight of a sulfurized calcium alkyl phenate, in which the alkyl group contains 12 carbon atoms. The total base number (test D-664) of this mixture is 126.

t A commercially available mixture of about 50% by weight of mineral oil and about 50% by weight of an alkenyl succinimide type ashless dispersant sold under the trade name of Oronite 120019. The mixture contained about 2% by weight llgtl'ogil and total base number (ASTM test D-664) of a ou 5 A commercially available mixture of about 50% by weight of mineral oil and about 50% by weight of a sulfurized olefin comprising an average of about 16 carbon atoms per molecule. The mixture, sold under the trade name of Oronite OLOA 231, contained about 17.5% by weight of sulfur and about 1.8% by weight of chlorine.

' Dow-Corning silicon anti-foam agent.

This composition along with two commercially available oils, referred to as Oils A and B and described below, were utilized to lubricate three White Superior Model 8GT 825 turbo-charged engines. Each of these four cycle engines, which have eight cylinders, was used to either directly compress natural gas or as part of a refrigeration system used to liquify the gas. All three engines endured similar work loads throughout the test period.

Each of the engines was fuel by a naturally occurring mixture of hydrocarbons consisting essentially of compounds containing from 1 to 3 carbon atoms per molecule. This fuel was essentially lead-free. The engines were equipped with Stellite inserts at the points of contact between the exhaust valves and the cylinder heads. The amount of valve wear was determined by periodically measuring the distance from a fixed point above the rocker cover base of the cylinder head to a fixed point on the exhaust valve stem. As the valve sinks or recedes into the cylinder head, this distance decreases. The decrease in distance represents the amount of valve wear. A depth micrometer was used to measure this distance. Each engine included eight cylinders and, in order to get a more accurate wear determination, measurements to two points on each exhaust valve stem were averaged.

Both of the commercially available products tested along with the lubricating oil composition noted above were SAE 40 lubricating compositions based on mineral oil. Oil A contained, on an elemental basis, about 0.011% by weight phosphorous and yielded about 0.84% by Weight of sulfated ash. Oil B contained zinc dithio phosphate. Neither commercial product contained an alkaline earth metal salt of a condensation product of an alkylene polyamine, an aldehyde, and a substituted phenol. On an elemental basis, Oil A did contain about 0.46% by weight of alkaline earth metal, While Oil B included about 0.5% by weight of alkaline earth metal.

A summary of the results of the valve sink tests is as follows:

TABLE Engine lubricated with the above-defined composition according to the 5 present invention (Example 1) Average distance from fixed point above rocker cover base to fixed point on exhaust valve B The negative wear measurements are the result of small inaccuracies in measurement. This result indicates that very little, if any, exhaust valve wear took place after 142 days in the engine lubricated according to the present invention.

Engine lubricated with commercially available Oil B Average distance from fixed point above rocker cover base to fixed point on exhaust valve stem, in.

Initial measure- After Aiter Alter Cylinder number ment 49 days 106 days 142 days Average amount of wear, in +0. 015 +0. 016 +0. 037

Engine lubricated with commercially available Oil A Average distance from fixed point above rocker 40 cover base to fixed point on exhaust valve stem, in

Initial measure- After After After Cylinder number ment 49 days 106 days 142 days Average amount of wear, in.-. +0. 015 +0. 028 +0. 035

The above data clearly demonstrate that the compositions of the present invention, whenused to lubricate internal combustion engines fueled by substantially leadfree natural gas, result in unexpectedly superior engine exhaust valve recession control relative to the exhaust valve recession wear experienced using commercially available lubricating oil compositions.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a method for lubricating an internal combustion engine fueled by substantially lead-free natural gas, wherein a lubricating amount of a lubricating composition is maintained on the components of said internal combustion engine requiring lubrication, the improvement which comprises maintaining on said components a lubricating composition comprising a major proportion of oil of a lubrieating viscosity; at least one alkaline earth metal sulfonate present in an amount suflicient to improve the detergency of said composition; and at least one alkaline earth metal salt of a condensation product of an alkylene polyamine having the following structure:

wherein R is an alkylene radical containing from about 2 to about 6 carbon atoms, and n is an integer from 1 to about 10, an aliphatic aldehyde containing from 1 to about 3 carbon atoms per molecule and a substituted phenol comprising an alkylated monohydric phenol containing at least one alkyl group of sufiicient size to impart oil solubility to said alkaline earth metal salt, said condensation product prepared by reacting from about 0.5 mole to about 2 moles each of said aliphatic aldehyde and said substituted phenol for every basic nitrogen atom present in said alkylene polyamine, said alkaline earth metal salt being present in an amount sufiicient to inhibit the recession of the exhaust valves of said internal combustion engine into the cylinder head of said internal combustion engine.

2. The method of claim 1 wherein said alkaline earth metal salt of a condensation product is a calcium salt.

3. The method of claim 2 wherein said alkaline earth metal salt of a condensation product is present in an amount from about 0.1% to about by weight of the total lubricating oil composition.

4. The method of claim 3 wherein said internal combustion engine is equipped with Stellite exhaust valve inserts and said substituted phenol is an alkyl phenol in which the alkyl group contains from about 4 to about 20 carbon atoms and said aldehyde is formaldehyde.

5. The method of claim 4 wherein said alkylene polyamine is diethylenetriamine.

6. The method of claim 1 wherein said composition contains at least one compound selected from the group consisting of alkali metal phenate, alkaline earth metal phenate and mixtures thereof, said compound being present in an amount suflicient to contribute alkalinity to said composition.

7. The method of claim 6 wherein said compound is an alkaline earth metal phenate.

8. The method of claim 7 wherein said compound is a calcium phenate and is present in an amount from about 0.1% to about 8% by weight of said composition, and said alkaline earth metal salt of a condensation product is a calcium salt.

9. The method of claim 8 wherein said alkaline earth metal salt of a condensation product is present in an amount from about 0.1% to about 6% by weight of the total lubricating oil composition and said calcium phenate is present in an amount from about 0.2% to about 6% by weight of the total lubricating oil composition.

10. The method of claim 9 wherein said substituted phenol is an alkyl phenol in which the alkyl group contains from about 4 to about 20 carbon atoms, and said aldehyde is formaldehyde.

11. The method of claim 1 wherein said composition contains from about 1% to about 6% by weight of at least one ashless dispersant, said ashless dispersant being a compound which comprises at least one hydrocarbon portion of sutlicient size to render said compound oil soluble and at least one nonmetallic polar portion which provides a substantial portion of the dispersant action.

12. The method of claim 3 wherein said composition contains from about 1% to about 6% by weight of at least one ashless dispersant, said ashless dispersant being a compound which comprises an alkenyl succinimide wherein the alkenyl group contains from about 30 to about 250 carbon atoms.

13. The method of claim 6 wherein said composition contains from about 1% to about 6% by weight of at least one ashless dispersant, said ashless dispersant being a compound which comprises an alkenyl succinimide wherein the alkenyl group contains from about 30 to about 250 carbon atoms.

14. The method of claim 8 wherein said composition contains from about 1% to about 6% by weight of at least one ashless dispersant, said ashless dispersant being 'a compound which comprises an alkenyl succinimide wherein the alkenyl group contains from about 30 to about 250 carbon atoms.

15. The method of claim 10 wherein said composition contains from about 1% to about 6% by weight of at least one ashless dispersant, said ashless dispersant being a compound which comprises an alkenyl succinimide wherein the alkenyl group contains from about 30 to about 250 carbon atoms.

16. The method of claim 3 wherein said composition contains an additive which comprises a chloro-sulfur substituted olefin.

17. A method of claim 10 wherein said composition contains an additive which comprises a chloro-sulfur substituted olefin having from about 10 to about 24 carbon atoms per molecule, said additive being present in the composition in an amount from about 0.1% to about 2.0% by weight of said composition and in an amount sufiicient to improve the corrosion inhibiting properties of said composition.

References Cited UNITED STATES PATENTS 2,280,419 4/ 1942 Wilson 25233 2,313,248 3/1943 Lincoln et a1 25248.8 2,344,988 3/1944 Kavanagh et a1 25242.7 2,816,867 12/1957 Moore et al 25233.4 3,424,679 1/1969 Allphin 25233 FOREIGN PATENTS 1,000,883 8/1965 Great Britain 25242.7

PATRICK P. GARVIN, Primary Examiner A. H. METZ, Assistant Examiner US. Cl. X.R. 25242.7, 48.8

mg UNITED STATES PATENT OFFICE- CERTIFICATE OF CORRECTION Patent NO. I 8Il Dated March 1974 Inventor(s) Robert C. Palmer It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

C lunm B/ line 73; delete the letter "a" and insert in place thereof --a,n oil compatiblem signed'and sealed this 2nd day of July 1974,

(SEAL) Attest:

v EDWARD M. FLETCHERJR. C.MARSHALL DANN Attestlng qfflcer Commissioner of Patents 

